Suitable for various types of batteries with terminal diameters of 15-17 mm. To engage the power, simply tighten the green thumbwheel slightly. Loosen it slightly to cut off the power. Battery and system master cut-off switch, save your car's power, protect the entire system from draining out. For 6V, 12V and 24V battery systems, 500 Amp surge rating and 125 Amp continuous rating. Easy to turn off power cut-off switch, allowing you to quickly disconnect your battery for safety, car maintenance or storage. Universal for cars, boats, trucks, RVs and more.